What recession? It is a question Tadashi Yanai has every right to ask after the founder of the company behind the discount clothes store Uniqlo was today declared the richest person in Japan, with a fortune estimated at $9.2bn (£5.7bn).

Yanai, president of Fast Retailing, has added $3.1bn to his fortune over the past 12 months to keep him at the top of the country's rich list for the second year running, according to Forbes Asia magazine.

Fast Retailing has benefited from strong sales of Uniqlo's cheap range of casual clothes at the same time as weak consumer spending has battered the profits of other Japanese retailers.

The firm recently reported a 57.2% jump in net profit from a year earlier to ¥34.9bn (£230m) for the three months to November, thanks to brisk sales of imitation leather jackets, fleece sweaters and its line of HeatTech garments made from heat-trapping fabric.

Uniqlo stores in Japan recorded a 20.8% increase in sales in the same period, having initially forecast a modest 3% rise in sales for the year ending in March. Fast Retailing, whose shares have gained 36% in the past year, raised its full-year profit forecast by 8.9%.

Yanai's Uniqlo empire includes 790 stores in Japan and 120 overseas, where it is competing with global apparel powerhouses such as Gap, Zara and H&M.

Yanai, Fast Retailing's biggest shareholder with a 27% stake, plans to add to the firm's single US store in New York and boost Uniqlo's presence in Europe, India and China.

"We want to make sales from overseas operations four times as large as those from domestic operations in 10 years," Yanai told reporters on a trip to New York this week to collect the retailer of the year award.

"Asia has the number one potential for growth and our operations there will become a leading revenue source."

Uniqlo's Japanese stores currently account for about 80% of the group's total revenue.

Nobutada Saji, the chief executive of Suntory Holdings, rose to second place in the Japan rich list after his firm entered merger talks with its bigger rival Kirin Holdings to create an Asian drinks maker capable of competing with the likes of Nestlé, Anheuser-Busch and Coca-Cola.

Saji's wealth has more than doubled over the past year to $8.6bn, Forbes said.

The magazine said a 31% rise in the value of the Nikkei benchmark index last year had benefited Japan's business elite, despite the return of deflation to the world's second biggest economy.

Japan's 40 richest people saw their net worth increase 25% to $87bn, Forbes said, with two-thirds of the increase attributed to the four top-earning tycoons. Forbes's figures also showed that the wealth gap has widened between those at the top and bottom of the list.